Illuminating device



y 1938- E. s. BISSELL ILLUMINATING DEVICE Filed Dec. 8, 1934 EVERETT S.BISSELL.

ATTORNEY Patented May 10, 1938 ILLUMINATING- DEVICE Everett S. Bissell,Irondequoit, N. Y., assignor to Bausch & Lomb Optical Company,Rochester, N. Y., a corporation of New York Application December 8,1934, Serial No. 756,674

Claims. (Cl. 240-1) The present invention relates to illuminatingdevices and more particularly to a unit for illuminating comparisonoptical instruments such as colorimeters, hemoglobinometers, comparisonmicroscopes or the like.

One of the objects of the present invention is to provide a new andimproved illuminating unit for comparison optical systems. Anotherobject is to provide a lamp unit for projecting two separate andrelatively variable beams of light. A further object is to provide alamp for projecting two beams of light inwhich both beams may besimultaneously reduced. A further object is to provide a lamp having twoangularly related plane reflecting surfaces and a single source of lightmovable with respect to said surfaces to regulate the relative amount oflight reflected by each. These and other objects and advantages residein certain novel features of construction, arrangement and combinationsof parts as will hereinafter be more fully set forth and pointed out inthe appended claims.

Referring to the drawing:

Fig. 1 is a perspective view of a lamp made in accordance with thisinvention.

Fig. 2 is a horizontal section of same.

Fig. 3 is a vertical section taken on line 3-3 of Fig. 1.

Fig. 4 is a detail view of the lamp mount.

A preferred embodiment of the invention is illustrated in the drawingwherein Ill indicates generally a housing having an upper portion II anda bottom l2 fastened to the upper portion by screws 13. The interior ofthe housing is made diffusely reflecting by coating it with a metallicpaint such as aluminum paint. The top of the upperportion H has twoopenings l4 in which two plane glass windows l5 and I6 are held by tworings I1 and I8. symmetrically arranged with respect to the openings I4is a third opening l9 and a bolt 20 is screwed into the portion lladjacent the opening l9. A plate 2| has an extension 22 provided with aslot 23 for engaging the bolt 20. The plate 2| also has an opening 24 inwhich a ring 25 carrying a lamp socket 26 is held by a screw 21. A lamp28 is fastened into the socket 2G.

Welded or otherwise suitably secured to the bottom plate I2 is ametallic plate 29 bent at 30 to form two plane angularly relatedsurfaces 31 and 32. The plate 29 is symmetrically located beneath thewindows l5 and I6 and each of. surfaces 3| and 32 is coated with a whitereflective paint. As the opening I9 is larger than the base of the lamp28, and the slot 23 is larger than the bolt 20, it is apparent that thelamp 28 can be freely moved within the housing In. As the lamp 28 ismoved across the casing it is moved toward one reflective surface of theplate 29 and away from the other reflective surface and hence 5 theintensity of the beam reflected through one window is increased Whilethe intensity of the beam through the other window is decreased.

Directly beneath the lamp 28, the bottom plate I2 is provided with ahole 33 in which a shaft 34 is rotatably mounted. A shutter 35 isfastened to the shaft 34 within the housing by means of a nut 36 and anoperating handle 31 is fastened to the shaft 34 outside the housing bymeans of a nut 38. The shutter 35 is movable to a position between thelamp 28 and the reflective plate 29 and in the position reduces thetotal light passing through the windows 15 and I6 by approximately onehalf. By the use of this shutter, the light source 28 may be madesufficiently powerful to permit the use of the unit in a brightlylighted room and yet be dimmed to a suitable extent when the unit is tobe used in a dark room. A ventilating opening 39 in the rear of the lamphouse permits the escape of heated air.

With the present invention it is possible not only to equalize the twolight beams, but it is also possible to compensate for slightdifferences in transmission between the two optical sytems of thecolorimeter or other instrument used. Thus if one optical system has alower transmission than the other due to dirt or some other cause, thebeam entering that system can be made stronger until the two beamsreaching the eye piece are equal in intensity.

While the two diffusely reflecting surfaces 3| and 32 are shown asangularly related at an obtuse angle, they may also be positioned at anacute angle to each other. That is, the plate 29 may be bent inwardlyrather than outwardly and 40 still accomplish the same result. The twoopenings l4 may, of course, be replaced by a single opening extendingacross the top of the lamp house. Such a construction would be easierand cheaper to manufacture.

From the foregoing it is apparent that I am able to attain the objectsof my invention and provide an illuminating lamp for projecting twoseparate and relatively variable beams of light. Various modificationscan, of course, be made without departing from the spirit of myinvention or the scope of the appended claims.

I claim:

1. An illuminating device comprising a housing having means permittingthe passing of two spaced beams through one wall thereof, two fixedangularly related, diffusely reflecting members within said housing, onefor each beam, a single light source movably mounted within said housingfor regulating the .relative amounts of light reflected in each beam,means for clamping the light source in adjusted position and a shutterwithin said housing for controlling the amount of light reaching saidreflecting members.

2. An illuminating device comprising a housing with a difluselyreflecting interior having two spaced openings in one wall, two plane,angularly related white reflecting members within said housing, one foreach opening, a slotted plate outside of said housing, a bolt on saidhousing extending through said slot for clamping said plate in desiredposition, a source of light carried by said plate and extending intosaid housing through a third opening therein and a shutter movablymounted within said housing for movement to and from a position betweensaid source and said members.

3. An illuminating device comprising a housing having means permittingthe passage of two spaced beams through one wall thereof, two fixed,angularly related, diffusely reflecting members within said housing, onefor each beam, a

single light source movably mounted within said housing for regulatingthe relative amounts of light reflected in each beam, and means forclamping the light source in adjusted position.

' 4. An illuminating device comprising a housing with a diffuselyreflecting interior having two spaced openings in one wall, two plane,angularly related white reflecting members within said housing, one foreach opening, a slotted plate outside of said housing, a bolt on saidhousing extending through said slot for clamping said plate in desiredposition, and a source of light carried by said plate and extending intosaid housing through a third opening therein.

5. An illuminating system for projecting two light beams of variableintensity comprising two plane reflectors positioned in inclinedintersecting planes, a concentrating reflector facing said planereflectors and fixedly positioned so that its optical axis substantiallybisects the angle between said plane reflectors, a single source oflight adjustably mounted between said concentrating reflector and saidplane reflectors and means for moving said light source relative to saidreflectors.

EVERE'I'I' S. BISSELL.

